There have been known a variety of techniques concerning manufacture of a recording material, one of them being a technique of matting the obverse and/or reverse surfaces of a photosensitive material for preventing static charges from accumulating on the material and preventing neighboring photosensitive material portions from adhering to one another and for improving vacuum adhesion property. As an example, when a photographic original film is superimposed on a photosensitive material during a light exposure step and light exposure is applied through a film of original picture for forming an image on the photosensitive material, it is necessary for the original picture film to be contacted tightly to the surface of the photosensitive layer of the photosensitive material to effect light exposure to preclude blurring of exposed image due to a gap between the surface of the photosensitive layer and the original picture film superposed thereon to obtain a clear image. A conventional practice is to put the photosensitive material and the original picture film between a rubber sheet and a glass plate of a vacuum printing frame and to establish a vacuum between the glass plate of the printing frame and the rubber sheet to bring them into tight contact with each other. This method is referred to as a "vacuum adhesion method". It has also been contemplated and practiced to provide a photosensitive layer for matting the layer for significantly reducing the evacuating time for tight contact as disclosed in JP Patent KOKAI Publication No. 51-111102 (1976). For matting the photosensitive layer, that is for formation of micro-sized patterns on the photosensitive layer, there are known methods described in, e.g., JP Patent KOKAI Publication Nos. 51-96604 (1976), 51-98505 (1976), 55-12974 (1980), etc.
Recently, a so-called double-sided photosensitive material, in which photosensitive layers are provided on both surfaces of its support, has become extensively popular. If attempts are made to use such photographic material to provide a fine pattern on both surfaces of the photosensitive layer by a gravure coating method, as described for example in JP Patent KOKAI Publication No. 51-96604 (1976), it is necessary to apply the fine pattern on one surface and allow it to be dried and subsequently to apply the fine pattern on the opposite surface and allow it to be dried. The device used for this purpose tends to be bulky in size. Besides, the portions of the reverse surface of the photosensitive material coated with the fine pattern tends to be delaminated or crushed by frictional contact with transport rollers during the process. This leads to a prolonged evacuation time for tight contact in case of image exposure on the reverse surface as compared to the case of that on the obverse surface. In addition, the portion of the reverse surface coated with the fine pattern, exposed to light subsequently in the course of the light exposure process, tends to be pressed by a printer during evacuated light exposure of the obverse surface and thereby crushed leading to a protracted evacuation time in the course of light exposure of the reverse surface.
The JP Patent KOKAI Publication No. 51-98505 (1976) shows a method of dispersing a wax-like resin or fine resin powders exhibiting mold release properties in a low boiling point organic solvent and spraying with an air spray for preventing the coating layer intended to improve the vacuum adhesion property from possibly contaminating the photographic original film. However, this coating layer tends to detach due to low adhesive force with respect to the photosensitive photographic film surface to incur the above-mentioned problems, as well. Besides, use of the organic solvents is not desirable from the viewpoint of safety during manufacture.
On the other hand, the JP Patent KOKAI Publication No. 55-12974 (1980) discloses a method of sprinkling solid powders on the presensitized printing plate for thermally affixing the solid powders on the printing plate. This method has a problem in that, if the presensitized printing plate is of the double-sided type, the mat layer on one side tends to be crushed before cooling during roller transport after adhesion by heat fusion. On the other hand, it is difficult from the viewpoint of handling to transport the printing plates without using the rollers. Besides, the resin needs to be pulverized and classified in size for producing the powders to raise manufacture costs.
In addition, the JP Patent KOKAI Publication No. 55-101951 (1980) discloses a method of causing solid powders to be uniformly dispersed and affixed to the surface of a continuously travelling presensitized printing plate. The device used for this purpose tends to be complex and bulky in size because of the provision of a pressurized air supplying device, powder supplying device, ejector, distributor, cyclone, etc., and suffers from a defect that the solid powders tend to detach during transport of the double-sided presensitized printing plate.
For solving the aforementioned problems, the JP Patent KOKAI Publication No. 57-34558 (1982) discloses a method of spraying an aqueous solution containing a resin dissolved or dispersed therein on the surface of the presensitized printing plate having a photosensitive layer on a support thereof and drying the aqueous solution. Although this method gives highly satisfactory mat properties, it has disadvantages as to propriety in manufacturing. That is, if an air spray is used, since it provides an extremely low rate of deposition of fine droplets amounting only to 10%, droplets which have not become deposited contaminate the inside of the coating chamber as overspraying. In an extreme case, the aqueous solution is likely to be affixed to a plate under spray-coating as a lump of wasteful resin. An electro-static spraying system, assuring a deposition rate of approximately 90% or higher, has been devised for diminishing the overspraying.
However, the following problem is met when the aqueous solution is applied by an electrostatic spraying system. First, with the electro-static spraying system, since fine droplets are attached to static charges, those droplets which can not contact strongly with the surface to be spray-coated, such as extremely small-sized or highly viscous droplets which are dried to some extent during a period of time after being atomized before being affixed to the surface to be spray-coated, are affixed to the surface of a recording material in the spherical-shaped states. This provides only a small contact surface and consequently a low binding force. In an extreme case, the droplets remain affixed merely electro-statically to the surface to be spray-coated. The result is that, if the photosensitive material is transported in contact with rollers or the like, the droplets which have been affixed are detached so that the evacuating time for tight contact can not be reduced as in the case of the above-described prior-art method. In addition, the film for the original picture or the transport rollers tend to be contaminated. Besides, with a bell or disc type device, the aqueous solution tends to be dried at the portions of the bell or disc where liquid flow of a thin film is obstructed to allow the resin to be precipitated and/or to interfere with the atomization process. Incidentally, the precipitated resin tends to become affixed to the article to be spray-coated.
For overcoming these problems, there is disclosed in U.S. Pat. No. 4,781,941, which corresponds to JP Patent KOKOKU Publication No. 61-48994 (1986), a method of matting a pre-sensitized printing plate. The method is comprised of electrostatically providing fine droplets of an aqueous liquid with a resin resolved or dispersed therein on the obverse surface and/or reverse surface of the pre-sensitized plate and thereafter, drying the fine droplets. The method is characterized in that before and/or after the attachment of the droplets, the surface of the pre-sensitized plate is wet. On the other hand, the JP Utility Model KOKAI Publication No. 59-65763 (1984) discloses a bell structure for preventing resin precipitation.
However, these methods are disadvantageous in that they necessitate complicated devices which can be produced only with expenditure of immense costs and labor.
If an ink jet system is used, the problem of the droplets being detached at pass rollers or contaminating ambient casing parts may be overcome. However, since oscillating elements, electrodes, etc, are necessitated for each nozzle, the mechanism tends to become complex and expensive to manufacture.
The foregoing description is directed to an example of improving vacuum adhesion property of the photosensitive material by matting the photosensitive material. However, the matting of the photosensitive material is also applied for preventing electro-static charging and self-agglutination or adhesion of the photosensitive materials to one another. Also, not only the obverse surface but also the reverse surface of the photosensitive material is occasionally matted. The same problems as those met when the vacuum adhesion property is to be achieved as described above are met with the matting carried out for these purposes.